diff options
Diffstat (limited to 'block/qcow2-cluster.c')
| -rw-r--r-- | block/qcow2-cluster.c | 39 |
1 files changed, 39 insertions, 0 deletions
diff --git a/block/qcow2-cluster.c b/block/qcow2-cluster.c index 057dac573..d4631c397 100644 --- a/block/qcow2-cluster.c +++ b/block/qcow2-cluster.c @@ -684,6 +684,7 @@ uint64_t qcow2_alloc_cluster_offset(BlockDriverState *bs, int l2_index, ret; uint64_t l2_offset, *l2_table, cluster_offset; int nb_clusters, i = 0; + QCowL2Meta *old_alloc; ret = get_cluster_table(bs, offset, &l2_table, &l2_offset, &l2_index); if (ret == 0) @@ -732,6 +733,44 @@ uint64_t qcow2_alloc_cluster_offset(BlockDriverState *bs, } nb_clusters = i; + /* + * Check if there already is an AIO write request in flight which allocates + * the same cluster. In this case we need to wait until the previous + * request has completed and updated the L2 table accordingly. + */ + LIST_FOREACH(old_alloc, &s->cluster_allocs, next_in_flight) { + + uint64_t end_offset = offset + nb_clusters * s->cluster_size; + uint64_t old_offset = old_alloc->offset; + uint64_t old_end_offset = old_alloc->offset + + old_alloc->nb_clusters * s->cluster_size; + + if (end_offset < old_offset || offset > old_end_offset) { + /* No intersection */ + } else { + if (offset < old_offset) { + /* Stop at the start of a running allocation */ + nb_clusters = (old_offset - offset) >> s->cluster_bits; + } else { + nb_clusters = 0; + } + + if (nb_clusters == 0) { + /* Set dependency and wait for a callback */ + m->depends_on = old_alloc; + m->nb_clusters = 0; + *num = 0; + return 0; + } + } + } + + if (!nb_clusters) { + abort(); + } + + LIST_INSERT_HEAD(&s->cluster_allocs, m, next_in_flight); + /* allocate a new cluster */ cluster_offset = qcow2_alloc_clusters(bs, nb_clusters * s->cluster_size); |